This invention relates to two embodiments of a planetary-motion engine, a rotary-piston engine and a reciprocating engine.
The internal combustion engines currently in use, in addition to the gas turbine engine, are the reciprocating engine and the Wankel rotary-piston engine.
The Wankel rotary-piston engine has many advantages, but it also has the following disadvantages. First, in the Wankel rotary-piston engine, it is impossible to raise the compression ratio high enough to sustain Diesel-engine operation. Second, the Wankel rotary-piston engine has two constrictions located on the minor axis of the contour of the normal section of the tubular cavity in the housing. These constrictions divide the working chamber along the minor axis into two parts, a trailing side and a leading side. Because of this division, when the engine cycle nears top dead center, the trailing side is compressed at the same time the leading side is expanded. This imbalance results in a loss of mechanical energy.
There is prior art that attempts to offer solutions to the abovementioned problems of the Wankel rotary-piston engine. JP, A, 49-46009 (May 2, 1974, Swiss National Patent No. 012260/72) discloses a rotary piston engine comprising: (a) a housing containing a tubular cavity, (b) parallel guide members fixed to the base of the tubular cavity, (c) an eccentric wheel with a pilot wheel installed between the parallel guide members, (d) a crankshaft in which the main shaft of the eccentric wheel is attached to the crank pin, (e) a rotating piston attached to the eccentric wheel, and (f) only one gear train including an outer gear fixed to the crank pin and an inner gear fixed to the rotating piston.
In this rotary piston engine, as the crankshaft revolves, the pilot wheel slides between the parallel guide members at the same time as it reciprocates. The pilot wheel and the eccentric wheel each rotate on their own respective axes as they revolve around the crank pin. Thus, as the crankshaft revolves, the vertex of the rotating piston describes a curve that determines the contour of the normal section of the tubular cavity.
Further, the following prior art appears in the international search report of this PCT application. JP, A, 60-39361 (March 1, 1985, John Fenton, U.S.A.) discloses a rotary-piston engine comprising: (a) a housing containing a tubular cavity, (b) an eccentric shaft which is a output shaft, (c) an eccentric ring attached to the eccentric shaft, (d) a rotating piston attached to the eccentric ring, (e) one gear pair consisting of an outer gear fixed to the eccentric shaft and an inner gear fixed to the inside of the eccentric ring, and (f) a second gear pair consisting of an outer gear fixed to the outside of the eccentric ring and an inner gear fixed to the rotating piston.
In this rotary-piston engine, no gear is fixed to the housing. As a result, the vertex of the rotating piston cannot describe the curve that determines the contour of the normal section of the tubular cavity when the rotating piston is installed in the tubular cavity.
JP, A, 51-104110 (Sep. 14, 1976, Kimiaki Kusano, Japan) discloses materials for the surface of the rotating piston of a Wankel rotary-piston engine.
In an internal combustion engine, the higher its expansion ratio, the higher its thermal efficiency. To reach a high thermal efficiency requires a high expansion ratio. In other words, the engine must complete combustion before beginning the expansion part of the cycle. However, in the case of the high-revolution internal combustion engines now in practical use, it is impossible to complete combustion either in the reciprocating engine or in the Wankel rotary-piston engine. There is simply not enough time. Thus the expansion ratio substantially decreases, and the thermal efficiency is reduced.